Features of surface subsidence zones formed under the influence of underground mining of steeply dipping ore deposits in the Kryvyi Rih iron ore basin

Purpose. The study aims to investigate subsidence zones in the Kryvyi Rih Iron Ore Basin, considering their spatial distribution, geometric parameters, development dynamics, and formation factors determined by the applied ore deposit mining systems, as well as to assess their techno-environmental impact on natural and infrastructural objects in the region. Methods. The research is based on the analysis of satellite imagery and GIS tools in Google Earth for the identification and measurement of geometric parameters of subsidence zones. The terrain profiling function was utilized to determine the width, depth, and area of the collapse zones, as well as to analyze the dynamics of their expansion over time. Findings. As of today, 15 active subsidence zones with a total area exceeding 170 hectares have been identified in the Kryvyi Rih Iron Ore Basin. A correlation has been revealed between the geometric characteristics of the subsidence zones and the geotechnical conditions of ore deposit extraction, expressed through variations in the collapse shape coefficient. The historical dynamics of subsidence area changes over several decades indicate a gradual decrease in expansion rates after reaching the critical mining depth. However, irregular development patterns have been observed, with some zones undergoing steady expansion while others experienced sudden collapses linked to shear processes within the mined-out voids. It has been proven that backfilling with waste rock does not ensure long-term stability and can contribute to secondary collapses, especially in areas with complex hydrogeological conditions or significant underground voids. Originality. A collapse shape coefficient has been proposed for assessing the geometric parameters of subsidence zones and the conditions of their formation. A systematic analysis of the historical dynamics of subsidence area changes has been conducted, establishing trends in their spatial and temporal expansion. Practical implications. The obtained results can be applied for predicting further development of subsidence zones, assessing their risks to industrial and infrastructural objects, and developing alternative backfilling methods to ensure long-term geomechanical stability in the region.